Previous studies from this laboratory showed that skeletal muscle underlying the burn wound exhibits unique metabolic alterations which are not seen in muscles more distant to the wound. These alterations include an elevation in glucose utilization, increased conversion of exogenous glucose to lactate, increased proteolysis and increased release of amino acids. The muscles underlying the burn wound are also unable to stimulate glucose metabolism by insulin. The proposed work will extend these observations and will compare the following aspects of metabolism in muscles underlying, and distant from, the burn wound: a) transport of amino acids into cells and the incorporation of amino acids into proteins; sensitivity of protein metabolism of muscles to stimulation with insulin; b) action of branched-chain amino acids on muscle protein and amino acid metabolism; c) nucleotide metabolism in muscles; d) glycolytic intermediates in muscles; e) intracellular levels of sodium, potassium, calcium, magnesium, and phosphate in muscles; relationship to plasma electrolyte levels; f) infiltration of muscles by macrophages and fibroblasts; the role of non-muscle cells in metabolic alterations exhibited by thermally-injured muscle.